Hughes Electronics Corporation

K C Lim

Jan Grinberg

Ronald I Wolfson

Richard L Abrams

J David Margerum

E Sherman

A M Lackner

A compact scanned antenna which includes a radiator, a rotatable tube and a line source. The radiator is formed by plating a shaped dielectric core. It generates an antenna beam at an output aperture in response to a microwave signal at an input port. The line source generates a radiation sheet which is directed across a signal plane to the input pot. The tube has a cylindrical wall which is positioned across the signal plane. As the tube rotates, refractive or diffractive transmission structures pass through the signal plane. The refractive structures include linear segments which refract the wavefront of the radiation sheet. Because the wavefront slope at the radiator's aperture is a function of the wavefront slope at its input port, the antenna beam is scanned. The linear contour segments have the same inclination but are not colinear. This arrangement reduces the thickness of the tube wall. Phase coherence is achieved by an appropriate radial spacing of adjacent ends of contour segments. The diffractive structures are arranged to vary the spacing of diffraction rings as they pass through the signal plane. This produces scanned, first-order antenna beams. The line source is adapted to direct a predetermined one of these beams into the radiator.

Scanned antenna system and method

A scanning array antenna employs a solid rotating core having an anisotropic refractive index within an apertured waveguide that emits radiation in response to an input beam propagating through the waveguide. Rotating the core changes its refractive index relative to the input beam, causing the radiated beams to undergo an angular scanning. The solid rotating waveguide core can be formed from a dispersion of aligned elongate conductive members in an isotropic dielectric, from a liquid crystal medium, or from a dispersion of aligned elongate conductive members in a liquid crystal medium. The antenna is operable in reciprocal transmission and reception modes.

Scanning antenna with solid rotating anisotropic core

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Agoura, CA, United States of America

K C Lim